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Neuroanatomy and Brain Perfusion in Functional Somatic Syndromes
Published in Peter Manu, The Psychopathology of Functional Somatic Syndromes, 2020
Functional magnetic resonance imaging was used by investigators from Vanderbilt University, Nashville, Tennessee, to study central nervous system changes during painful stimulation in patients with irritable bowel syndrome (Mertz et al., 2000). The technique measured the ratio of oxyhemoglobin to deoxyhemoglobin, which was considered a marker for the local blood flow and metabolic activity. The activated area produced a magnetic resonance signal of higher intensity and allowed the precise definition of the activated anatomical site. The subjects recruited for the study included 16 patients with irritable bowel syndrome (14 women and two men with a mean age of 33 years) and 18 age- and gender-matched healthy individuals. The control subjects were free of abdominal pain and other complaints attributable to the gastrointestinal tract. Organic disease was ruled out in all participants by history and physical examination, comprehensive laboratory testing, and sigmoidoscopy or other endoscopic procedures.
The Respiratory System and Its Disorders
Published in Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss, Understanding Medical Terms, 2020
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss
The process by which oxygen passes from the alveoli into the bloodstream and carbon dioxide passes from the bloodstream into the alveoli is diffusion. Once the carbon dioxide from the blood reaches the alveoli, it is forced up and out. through the respiratory passages during expiration (Figure 9.2). The oxygen that has entered the bloodstream is carried to cells throughout the body by the protein molecule called hemoglobin. The term oxyhemoglobin refers to the molecule of hemoglobin when it is combined with oxygen.
Physiological Implications of Ferrihemoglobinemia
Published in Manfred Kiese, Methemoglobinemia: A Comprehensive Treatise, 2019
Studies of the structure of the hemoglobin molecule have shown that oxidation of the iron atoms causes similar changes of the tertiary structure of subunits and the quarternary structure of the hemoglobin molecule as oxygen liganding to deoxyferrohemoglobin.665–667,2299 This effect explains the increase in oxygen affinity by partial oxidation of hemoglobin. Differences between the structure of oxyhemoglobin and ferrihemoglobin and their bearing on the understanding of heme-heme interaction have been discussed by Perutz.2378
The impact of labyrinthine magnetic resonance signal alterations on the treatment of sudden sensory-neural hearing loss
Published in Acta Oto-Laryngologica, 2023
Edoardo Covelli, Chiara Filippi, Haitham H. Elfarargy, Luigi Volpini, Valerio Margani, Giulia Moltoni, Serena Palizzi, Andrea Romano, Alessandro Bozzao, Maurizio Barbara
Although we cannot be entirely sure that LSC is related to intra-labyrinth hemorrhage (especially when this was observed only on FLAIR sequences), it is known that the hyperintensity on FLAIR images involving the labyrinthine structures could be caused by hemorrhage, endolymphatic stasis (due to cerebellopontine angle lesions), and infective disorders. Considering the absence of these last conditions in our cohort of patients, we suggest that this finding might be related to intra-labyrinth hemorrhage. Furthermore, the evolution of hemoglobin in hemorrhage passes through predictable stages from oxyhemoglobin to hemosiderin. Therefore, in the subacute phase, the presence of methemoglobin in the labyrinth may produce high signal intensity on both T1 and FLAIR images. In the case of mild hemorrhagic components in the labyrinth, 3D FLAIR sensibility is likely higher than T1, and T1 might be normal despite a positive FLAIR. Based on this knowledge, we decided to obtain MRI in the subacute stage, 3–14 days after symptom onset evaluating FLAIR images and T1 to increase the likelihood of detecting possible intralabyrinthine hemorrhage [17]. For these reasons, we suggest that the higher incidence of LSC in our prospective study might be related to the different MRI techniques (volumetric FLAIR) and timing (within 15 days).
Co-delivery of carbonic anhydrase IX inhibitor and doxorubicin as a promising approach to address hypoxia-induced chemoresistance
Published in Drug Delivery, 2022
Muhammad Umair Amin, Sajid Ali, Muhammad Yasir Ali, Dominik C. Fuhrmann, Imran Tariq, Benjamin S. Seitz, Eduard Preis, Jana Brüßler, Bernhard Brüne, Udo Bakowsky
The determination of hemolysis was based on the extent of erythrocyte destruction and release of hemoglobin because of their interaction with different formulations. Free hemoglobin in the presence of atmospheric oxygen is converted to oxyhemoglobin which can be detected spectrophotometrically. The results of the hemolysis assay are shown in Figure 8(b), where free Dox, MSNPs, and Dox-MSNPs have shown hemolytic effects. The destruction of erythrocytes is attributed to the surface density of the silanol group of MSNPs (Bharti et al., 2015). On the other hand, CA-IX enzyme inhibitor-loaded liposomes have shown lower hemolytic effects. In the lipid coated formulations, the hemolytic effects of free Dox and MSNPs were significantly masked because of the biocompatible nature of liposomes.
“Popper” induced methemoglobinemia
Published in Baylor University Medical Center Proceedings, 2022
Fares Elgendy, Gaspar Del Rio-Pertuz, Dalena Nguyen, Drew Payne
Among the many substances linked to methemoglobinemia, amyl nitrite “popper”-induced methemoglobinemia cases are increasing at an alarming rate. Amyl nitrite products are sold in glass vials under the brand names Rush, Super Rush, Jungle Juice, Locker Room, Sub-Zero, and Iron Horse, among others. The diagnosis can be suspected by a suggestive history and confirmed with ABG analysis utilizing a co-oximetry to directly measure the oxygen saturation (percentage of oxyhemoglobin), as opposed to calculating it from the partial pressure of oxygen, which usually results in inaccurate results depending on oxygen supplementation.6 The unreliability of routine, two-wavelength pulse oximetry in cases of methemoglobinemia is due to methemoglobin’s ability to absorb light at both wavelengths emitted by the pulse oximeter, resulting in an inaccurate estimate of oxygen saturation that does not correct with oxygen supplementation; readings are usually in the 85% to 88% range, as seen in our patient, regardless of true oxygen saturation.7